Pentagon Calculator
MathCalculate the perimeter, area, diagonal, and radii of a regular pentagon from its side length.
Area
Area of the regular pentagon.
Perimeter
30.0000
Total perimeter.
Diagonal
9.7082
Length of a diagonal connecting two non-adjacent vertices.
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Odeh Ahwal0people find this calculator helpful
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Creators
Odeh Ahwal0people find this calculator helpful
Views
Helpful
Saved
Embeds
Math calculators
Frequently Asked Questions
How is pentagon area calculated?
Area equals the side length squared, times the square root of 25 plus 10 times the square root of 5, divided by 4, approximately 1.7205 times side squared.
Why does the diagonal involve the golden ratio?
A regular pentagon's diagonal-to-side ratio equals the golden ratio, 1 plus the square root of 5, divided by 2, approximately 1.618. This famous ratio appears naturally in regular pentagon geometry.
Is the US Department of Defense building actually a regular pentagon?
Yes, the Pentagon building in Arlington, Virginia is designed as a regular pentagon, with all five sides and angles equal, which is also where the building gets its name.
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